1. Field of the Invention
The present invention relates, in general, to an electric actuator and, more specifically, to an electric actuator for opening and closing the door to a vehicle.
2. Description of Related Art
Power door operators have been developed to reduce the strain on vehicle operators caused by the repeated opening and closing of vehicle doors. Many power door operators use pneumatic actuators because the air brake systems in mass transit vehicles provide a reliable and convenient source of air at controlled pressure. U.S. Pat. No. 4,454,685 is an example of such a power door operator.
Electric door actuators have also been developed. U.S. Pat. No. 5,332,279 discloses a power door operator for multi-passenger mass transit vehicles. This system uses electrical gear motor operating drive arms in order to open and close dual panel swing door sets. U.S. Pat. No. 6,125,768 discloses a door system for transit vehicles that uses an electrically driven operator to open and close the doors of a mass transit vehicle. Both of these prior art systems fail to efficiently use space and require motion in more than one plane of action.
Power door operators usually include an emergency release mechanism. A pre-existing design for the release mechanism is a toggle-based device. Such a toggle-based release mechanism is disclosed in U.S. Pat. No. 6,662,501.
Therefore, a need exists for an electric door actuator that maximizes space efficiency, while also ensuring that all motion occurs in a single plane. There is also a need for an actuator with a simple emergency release mechanism that is space and cost efficient.